I'm not qualified to wear the tartan, but I did a quick check of my bookmarked sites out of curiousity -

McRok.com - 8 yd 16 oz at $373.00 (doesn't say which Clergy)
ScottishLion.com - 8 yd 13 oz at $580.00 (Ancient, Blue Modern or Green Modern)
The Kilt Store (right up there in the corner) - 8 yd 16 oz at $509.84 (Ancient or Modern) and 13 oz at $460.95 (Muted). I'm not sure if that is with the 10% XMarks discount or not. They also have six variations in tartan fabric.